int a[8];
char *day[]
={"","MONDAY","TUESDAY","WEDNESDAY","THURSDAY",
  "FRIDAY","SATURDAY","SUNDAY"};
  main()
  {
    int i,t,j;
    a[4]=6;
    for(i=1;i<=3;i++)
    {
        a[i]=2;
        if(!a[1+3])a[1+3]=7;
        else{ a[i]=0;continue;}
        for(t=1;t<=3;t++)
        {
         if(!a[t])a[t]=5;
         else continue;
         if(!a[t+2])a[t+2]=4;
         else { a[t]=0;continue;}
         for(j=5;j<7;j++)
         {
          if(!a[j])a[j]=3;
          else continue;
          if(!a[j+1])a[j+1]=1;
          else{ a[j]=0;continue;}
          for(i=1;i<=7;i++)
          printf("Doctor %c is on duty %s.\n",'A'+a[i]-1,day[i]);
          exit(0);
         }  
        }
    }
  }